Method of making pipe-bends.



C. H TRUE & N. T. McKEE.

METHOD OF MAKING PIPE BENDS.

APPLICAHON ILED APR 30 1914 SHEET 1.

Patented Jan. 25, 1916.

2 SHEETS 5W IN l/ENTOR CHARLES H. TRUE NEAL T. M KEE BY (L H. TRUE & N.T MCKEEx METHOD OF MAKING PIPE BENDS.

APPLlCATlON FILED APR 30. 1914.

Patented Jan. 25, 1916 2 SHEETS--SHEET 2,

WITNESSES 15*" llVl/E/VTUR A CHARLES H. TRUE By/VEAL 71/M /f/IE 4;; 3 39 A TTOR/VEYS CHARLES H. TRUE, OF HAMMOND, INDIANA, AND NEAL TRIIVIBLEMGKEE, OF DOBBS FERRY, NEW YORK, ASSIGNORS T LOCOMOTIVE SUPERHEATERCOMPANY, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE.

METHOD OF MAKING PIPE-BENDS.

Application filed April 30, 1914;. Serial No. 835,360.

To all whom it may concern:

Be it known that we, Gunners H. TRUE and NEAL Tnnmne lhiol'inn, bothcitizens of the United States. residing, respectively, at Hammond,Indiana, and at Dobbs Ferry, New York, have inventedcertain new anduseful Improvements in Methods of Making Pipe-Bends, of which thefollowing is a specification.

Our invention relates to a method of making pipe bends, andparticularlyto making what are com mouly knowii as U-shaped be'iids, such as areused in connection with boilers, superheaters and heating apparatusgenerally and exposed to high temperatures, or when used'to carry steamor fluidsunder pressure.

' Our invention relates particularly to making bends as aforesaid whenthe two legs of the bend are required to be very close together.

The object of our invention is to providea method of making a strong anddurable bend which can be practised easily, eeonomically and at smallexpense.

A further object of our invention is to provide a method of making abend as specified in which the internal or free cross-sectional area maybe, at all points, fully as great, if not greater, than that of the individual pipes joined by the bend.

Still. afurther object of our invention is to provide a. method ofmaking a bend which,

i when employed as part of a superheater element of a smoke tubesuperheater, will not unduly restrict the flow of gases through the fluetube but will, on the other hand, facilitate the easy passage of saidgases while, at the same time, exerting no greater retarding efiect uponthe flow of steam through the bend than would be exerted by the samelength of the pipe joined by said bend.

Various ways of making bends for snmlar purposes have been proposed, butsuch ways are attended bycertain disadvantages which it is the purposeof our invention to obviate.

Our invention will. be better understood by referring to theaccompanying drawings which show preferred devices for carrying out saidinvention. in whieh- Figure 1 represents a. plan view-of a pair of pipeends in position .on the lower half of the female forming diepreparatory to hav- Specification of Letters Patent.

.which are to be around into the pipe lengths may rest.

I a pair of tapered legs 9, united Patented Jan. 25, 1916.

ing our improved pipe bend formed thereon; Fig. 2 is an end view of Fig.1 with the upper half of the female forming die in position; Fig. 3 is aview similar to Fig. 1,

showing the male forming die in position 7 is a section along the line 77 of Fig.

6 except that the upper member of the forging die is shown in position;Fig. 8 is a view, similar to Fig. 6, showing the pipe bend after theforging dies of'Fig. 7 have done their work; Fig. 9 is a section takenalong the line 99 of Fig. 8;-Fig. 10 is a plan view of the completedpipe bend; Fig; 11 is an edge view of Fig. 10; Fig. 112is a sectiontaken along the line l2-12 ofFig. 10; and 13 is a section taken alongthe line 13-13 of Fig. 10.

In the drawings, two pipe lengths 1, 2, united by a pipe bend, aresquared off at one end, as at a and clamped between two similar halves3, at of a female forming die. The lower member 4 of this die is shownin Fig. 4 and comprises a block having parallel semi-circular grooves 5corresponding to the pipe diameter. The intermediate partitionwall'orseptum between the grooves has one part 6 of the same height asthe outer part of the die and another part 7 which rises gradually froma minimum height just before it joins the part 6 which it does by gentlecurves which are carried grooves 5. Before placmg the pipe lengths inthe dies 3 and 4, their ends are raised to a welding heat. The dies 3and 4 must be securely clamped together, and it is best, also, to clampthe pipe lengths outside of the dies and to provide stops (not shown)against which the other ends of the The pipe lengths being inposition,as above described, a breaches die 8, comprising by web 10 and havingslightly pointed ends 11 for easy I insertion, is held by the shank 12in a suitable presstnot shown) and has its legs in sorted into the pipeends at a and is pushed home therein. As the web 10 reaches the inneradjacent walls 13 of the pipe ends, its a comparatively sharp thin edge13 will slit said walls and raise andl yer the slitted wall portionsagainst the parts 7 belonging to the upper and lower die respectivelyand compress said; slitted portions between the parts 7 and the web 10,which thickens toward its base so as to conform to the varying height ofthe part 7. If the dimensions of the forming dies and of the breechesdie are properly chosen, the upper and lower pair of slitted pipe wallswill just properly abut with welding pressure when the edge of the web10 is distant from the end of the part (iof the septum lying betweengrooves 5 by substantially the wall'thickness of the pipe. A perfectweld will thereby be formed, As will be evident from Fig. 3 the web 10whichunites the legs 8 has substantially the same shape as that of thespace uniting the bores of the female forming die; but this web issmaller in section than said space and is everywhere separated from theparts 7 by an amount substantially equal to the wall thickness of thepipes. This separating distance might, however,,if desired, be greaterat one point and less at another within the scope of the invention, theprime requisite being that the separating space must just take andcontain the slitted and spread pipe walls so asto bring their edgestogether with the necessary pressure to effect a satisfactory weld. Thebreeohes dies is then withdrawn, the forming die opened, and the pipelengths with the partially completed bend removed. Atthis stage intheoperation, the pipe bend will have the appearance shown in Figs. 6and 7, that is to say, the two pipes will be parallel to one another,and will retain their original shape at their ends, except in theconnecting region or yoke between them formed by the slitted parts ofthe pipe walls, which have been raised and lowered respectively andwelded. together as aforesaid. It will now .be necessary to suitablyclose the ends of the partially completed bend and at the same time togive said bend a suitable shape. These two operations may be carriedoutsimultaneously as follows: The forging die 15, comprising similarmembers, is used'in any suitable forging machine (not shown) after i themanner shown in Fig. 7. The preferred form of. the two similar membersof this forging die is indicated in Fig. 5 where the one part 16 isscooped out to correspond with the conformation of the com leted bend,while another part 17 is recessed y an amount substantially equal to thethickness ofythe pipe wall. A central recess 18 is comprised between theparts and provided at one end to'receivd a slipdie 19 which is insertedcentrallyfinto the par tially formed bend as shown in Fig. 6. With theinchoate pipe bend in position, as shown in. Figs. 6 and 7, the forgingdies are lightly operated so as to elfect a preliminary shaping. As soonas the central portion of the bend is flattened sufficiently to bindupon the slip die, the latter is withdrawn. The forging operation isthen continued until the bend has assumedthe appearance shown in Figs. 8and 9 where, so far as its form is concerned, it is complete except forthe fin 21 resulting from the flattening of the surplus wall-portionslying outside of the curve which is to form the outer boundary of thecompleted bend. ,The'small opening left at the end of the die by thewithdrawal of the slip die should have been closed by any suitable meansbefore the completion of the described forging operation. although, ifpreferred, it may be closed after the remainder of the forging operationhas been completed. Or, after the slip die has been removed we mayremove the incomplete pipe bond, as it thus exists, to a second pair offorging dies similar to those just described but having'no recess 18 forthe slip die. This second pair of dies will thus close the slip dieopening as well as the remainder of the pipe bend opening. It nowremains to remove this fin 21' and this, we find can be most easily doneby using an city-acetylene burner and running' around the pipe end atthe line of its junction with the fin so as to'cut the fin away. Bythenagain running the flame around the curved end whileprojecting itinto the plane of separation of the edges, the latter will be weldedtogether in a firm and durable weld. Or the fin may be cut oif byshearing in a suitable trimmingpress, or the equivalent, beforeproceeding to weld he edges together. v Instead of proceeding fromtheincomplete bend of Fig. 6 through the, form of Figs. 8 and 9, z. e.,instead of first compressing the ends so as to form the fin 21, and thencutting off said fin and welding the edges together, as just described,we may, if we prefer, first shear off all that portion of the incompletebend (Fig. 6) which lies between the extreme ends and thecurved line b.The edges at said line b may then be brought together by suitableforging dies, or by other suitable means, and then welded igogetherbythe oxyacetylene flame, as beore.

Other methods ofbringing the edges (at the curve 6) together orofwelding them durably when-brought together, may be employed within thespirit of our invention.

. By suitably shaping the forming dies the end 0. of our improved pipebend may be formed as a sharpedge from which the 40 lack of uniformityamong different bends as well as inefficiency in individual bends.

. thickness of the pipes proper when .and bend merge into one another.

pipes The bend is not quite so thick through the yoke 14 as at .thesides thereof, in the particular form of bend which has been described,this lessened thickness resulting, in effect, in the production of acentral groove on each side of the bend. The fire gases, as they reachthe end 0 of the bend, are split and divide and pass on past the bend,the two grooves facilitating the passage of the gases and, at the sametime, providing a larger heating surface for thegases to contact with.This groove is, however, not es sential to the practice of our inventionand may be omitted. Indeed, the form and proportions of the bend maybevaried widely without departing from the spirit of the invention and thesection through the bend (as shown in Fig. 13) may have any desired andconvenient form.

The cross-sectional area of the passage I through the pipe bend, at allpoints thereof,

can obviously be fully as great as that of the pipe itself, and as muchgreateras may be desired. .This is accomplished by choosing a suitablelength" and thickness for the web l0 and by correspondingly dimensioningthe forming'dies with which-the web must cooperate.

When the pipe bend, made as above de-' scribed, is completed (Figs.10-12) it is' practicallyimpossible to find the welds, 'so perfectly andsmoothly are the edges united. In particular, there will be no finsprojecting inwardly from the welds; such fins 005 I our in certain othermethods of pipe bend manufacture and are very diflicult if notimpossible to remove. If left in place such fins will restrict thepassage and produce a employedin shaping the bends and making the welds,may be .made-within the spirit of our invention as defined in thefollowing claims '-1.-The method of'.making pipe bends whichcomprisestakingtwo pipes and slitting the wall of each longitudinallyfor a suitable distance from the pipe end, pressing thepipe walls oneach side of said slits outwardly, causing the edges of the two slittedparts of one pipe to abut against corresponding edges of the other pipeand then welding said edges together, and finally.-

- closing the end of the incomplete bend thus formed.

2. The method of making. pipe bends which comprises taking two pipes andslitting the wall of each longitudinally for a suitable distance fromthe pipe end, pressing the pipe walls on each side ofsaid slitsoutwardly, pressing the edges of the two slitted parts .of one pipeforcibly against corresponding edges of the other pipe while said edgesare at welding heat thereby causing them to be united, and-finallyclosing the end of the incomplete bend thus formed.

3. The method of making pipe bends which comprises holding two pipelengths to be joined in the relative position they are to occupy whenthe bend is completed,-si-

multane'ously slitting neighboring walls of a pressing the slitted partsoutwardly until they abut. in-pairs, welding said abutting edgestogether, and finally closing the end of the incomplete bend thusformed.

5. The method of making pipe bends I which comprises holding twopipelengths to be joined in the relative position they are to occupy whenthe bend is completedand with their ends at welding heat, slittingneighboring walls of both pipes for a suitable distance from said ends,pressing the pipe walls on each side of each slit out'-. wardly untilsaid edges are abutted forcibly together in pairs thereby uniting themby a.-

complete bend thus formed.

In testimony whereof we have hereunto set our hands in the presence oftwo subscribing witnesses.

CHARLES H. TRUE; NEAL TRIMBLE MoKEE.

lVitnesses as to C. H. True:

M. J. SoNTAe, JAS. K. Sco'rr. Witnesses as to N. T. McKee:

W. SCHILLER. G. H. WINKIJER, Jr.

weld, and finally closing the'end of the in-

